Embolic implant and method of use

ABSTRACT

A parent artery occlusion (PAO) device which provides for immediate occlusion of a cerebral artery to isolate a defect. The PAO device includes a self-expanding wire-frame prolate structure which is partially covered with an ePTFE membrane.

This application a continuation of U.S. application Ser. No. 15/072,873,filed Mar. 17, 2016, which is a continuation of U.S. application Ser.No. 14/171,088, filed Feb. 3, 2014, now U.S. Pat. No. 9,301,827, whichis a continuation of U.S. application Ser. No. 13/483,962, filed May 30,2012, now U.S. Pat. No. 8,641,777, which claims the benefit of andpriority to U.S. Provisional Application Ser. No. 61/493,108, filed Jun.3, 2011. The entire content of each of these applications isincorporated herein by reference.

FIELD OF THE INVENTIONS

The inventions described below relate to the embolic devices for use inthe neuro-vasculature (cerebral arteries and veins).

BACKGROUND OF THE INVENTIONS

The devices described below are intended for treatment of defects in thecerebral arteries and veins. Defects of the cerebral arteries includeaneurysms, fusiform aneurysms, arteriovenous malformations,arteriovenous fistulas, cavernous fistulas and dissections and otherhyper-vascular lesions (head and neck tumors, etc.). These defects causeof variety of symptoms, ranging from headache and vision loss to strokeand death. Preferably, these defects would be treated with devices andtechniques that leave the associated parent artery or vein intact andpatent so that it may continue to supply blood to regions of the brainwhich it naturally supplies. Such techniques include filling an aneurysmwith occlusive polymers or occlusive coils, or inserting stents orcovered stents, where feasible. In many cases, however, this is notadvisable or possible because the artery vein segment in which thedefect, or the defect itself, will not accommodate the devices, orbecause the patient's condition indicates that immediate cessation ofblood flow is required.

The alternate, when parent artery preservation is not advisable, isparent artery occlusion, or PAO. Parent artery occlusion is accomplishedby quickly and securely closing off a length of a blood vessel near thedefect, and preferably results in immediate and complete blockage ofblood flow to the defect, and permanent isolation of the blood vesselsegment near the defect. Parent artery occlusion is sometimes referredto more broadly as parent vessel occlusion, to encompass occlusion ofboth arteries and veins. Several endovascular devices and techniqueshave been developed to accomplish parent artery occlusion. Detachableballoons have previously been proposed and used for parent arteryocclusion, but were not successful because the balloons to often leakedand deflated, leading to major embolic complications. (GiantIntracranial Aneurysms at 257 (Awad, Issam and Barrow, Daniel, eds.,Thieme/AANS 1st ed., 1995)). Occlusive coils have been used to packfusiform aneurysms and cavernous fistulas, but this is extremelyexpensive (it may require dozens of coils) and does not result inimmediate occlusion. Thus, trickling blood flow, which occurs forseveral minutes while the patient's blood is coagulating around the massof coils, may lead to creation and migration of thrombus from the massof coils. Vascular plugs have been used to accomplish parent arteryocclusion. Currently available plugs, such as the Amplatzer vascularplug, are used off-label in the neuro-vasculature, and are difficult todeploy. Ross, et al., The Vascular Plug: A New Device for Parent ArteryOcclusion, 28 AJNR Am J Neuroradiology 385 (February 2007). Also, theopen-mesh construction of these vascular plugs may result indislodgement of thrombus as it is forming on the plug, leading toembolization downstream of the occluded artery.

SUMMARY OF THE INVENTIONS

The devices and methods described below provide for expeditiousembolization of arteries of the neuro-vasculature with an embolicimplant, and suitable for use as a parent artery occlusion device withina cerebral artery (or within a cerebral vein). The devices may also bedeposited in aneurysms. The embolic implant includes a self-expandingcage-like wire-frame structure, which may be elongate or spherical, oroblate or prolate spheroid, which is covered with a polymer membrane.The embolic device is releasably attached to the delivery catheter withmechanical attachment means such as detents, electrolytic detachment orother suitable detachment means. Upon release from the deliverycatheter, the embolic device expands toward its unrestrained shape, tothe extent allowed by the surrounding cerebral artery. Expansion of thecage like structure, and concurrent expansion of the membrane, resultsin immediate occlusion of the cerebral artery. In recent comparativestudies, the embolic implant stopped blood flow in an artery in about 15seconds, as compared to the Amplatzer™ vascular plug, which took 3minutes to stop blood flow.

Additionally these devices are used to perform pre-operativede-vascularization and test occlusions. Additional embolic implants arealso disclosed, which include cage-like bodies formed with struts andrestraining bands. Though proposes for use within the cerebralvasculature, the devices may also be used to treat defects blood vesselsthroughout the body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the vasculature of the brain showing atypical placement of an intra-cranial embolic device.

FIG. 2 is schematic diagram of the vascular of the brain illustratingthe circle of Willis and arteries supplying the circle of Willis.

FIG. 3 illustrates an embolic implant with a oblong prolate wire-framestructure which is partially covered with a membrane.

FIG. 4 illustrates the several segments of the parent artery occlusiondevice.

FIG. 5 illustrates a side view of an embolic implant, comprising aplurality of longitudinal struts, in its unexpanded state.

FIG. 6 illustrates a side view of an embolic implant of FIG. 5 , whichhas been radially expanded by foreshortening the distance between itstwo ends.

FIG. 7 illustrates a side view of the unexpanded embolic implant of FIG.6 releasably affixed to the distal end of a delivery catheter andfurther inserted through the lumen of a guide catheter along with aguidewire.

FIG. 8 illustrates a side view of the embolic implant of FIG. 6releasably affixed to the distal end of the delivery catheter andadvanced out the distal end of the guide catheter along with theguidewire, allowing the implant to expand radially.

FIG. 9 illustrates the expanded embolic implant of FIG. 2B wherein theguidewire has been withdrawn so that the distal end of the guidewire isproximal to the proximal end of the implant such that the implant isreleased from the delivery catheter.

FIG. 10 illustrates the embolic implant of FIG. 9 wherein the deliverycatheter has been withdrawn proximally away from the released embolicimplant.

FIG. 11 illustrates the embolic implant of FIG. 7 , rotated 90 degrees,in a side partial breakaway view such that the releasable lockingmechanism is illustrated.

FIG. 12 illustrates the embolic implant of FIG. 11 in partial breakawayview with the guidewire having been withdrawn and the locking mechanismreleased from the embolic implant.

FIG. 13 illustrates a side view of an embolic implant comprising aplurality of radially expandable struts over which a membrane has beenaffixed.

FIG. 14 illustrates a side view of an embolic implant comprising aporous mesh disposed over, and affixed to, the expandable struts.

FIG. 15 illustrates a side view of an embolic implant comprising aplurality of struts affixed to a cylindrical proximal end and comingtogether at the distal end such that substantially nothing projectsdistally of the struts.

FIG. 16 illustrates an end view of the embolic implant of FIG. 8Ashowing how the struts come together at the distal end.

FIG. 17 illustrates a side view of an expanded embolic implant stillconnected to its delivery catheter, with its delivery sheath partiallyretracted and shown in cross-section, wherein the implant comprises aplurality of longitudinally disposed struts or bars connected togetherat the proximal and distal end and further including a thin, polymericmembrane surrounding the proximal portion of the implant.

FIG. 18 illustrates a side view of an expanded embolic implant stillconnected to its delivery catheter but with the delivery sheathretracted out of the illustration, wherein the embolic implant comprisesa plurality of longitudinally disposed struts interdigitated with aplurality of partial longitudinal struts and further partially coveredwith a membrane.

FIG. 19 illustrates a side view of a collapsed embolic implant attachedto its delivery catheter and disposed within its delivery sheath,wherein the implant comprises a mesh.

FIG. 20 illustrates a side view of the embolic implant of FIG. 19wherein the sheath has been withdrawn to expose the implant allowing itto expand diametrically.

FIG. 21 illustrates a side view of an embolic implant totally separatedfrom its delivery catheter and sheath wherein the embolic implantcomprises a plurality of longitudinal struts further comprising aplurality of serpentine segments in the center region of thelongitudinal struts.

FIG. 22 illustrates a side view of an embolic implant totally separatedfrom its delivery catheter and sheath, wherein the implant comprises aplurality of longitudinally disposed struts in its proximal centralregion and a mesh in its distal central region.

FIG. 23 illustrates a side view of an embolic implant comprising aplurality of longitudinal struts that each divide into three struts withthe division point being in the central region of the implant.

FIG. 24 illustrates a side view of an embolic implant comprising aplurality of longitudinal struts formed to generate two bulbs connectednear the center of the implant in a smaller diameter region.

FIG. 25 illustrates a side view of an embolic implant comprising aplurality of longitudinal struts interdigitated with flower petalstructures formed in outline by bent struts affixed to the distal end ofthe implant.

FIG. 26 illustrates a side view of an embolic implant comprising aplurality of longitudinal struts interconnected in the central region bylaterally disposed bars.

FIG. 27 illustrates a side view of an embolic implant comprising aplurality of longitudinal struts connecting a central mesh structure tothe proximal and distal ends of the implant.

FIG. 28 illustrates a side, partial breakaway, view of an embolicimplant coupled to a delivery catheter by means of a threaded,releasable linkage.

FIG. 29 illustrates a side, partial breakaway, view of an embolicimplant coupled to a delivery catheter by means of a meltable linkage.

FIG. 30 illustrates a side, partial breakaway, view of an embolicimplant coupled to a delivery catheter by means of a pressurized releasesystem.

FIG. 31 illustrates a side, partial breakaway, view of an embolicimplant coupled to a delivery catheter by means of an expandable couplerthat can be decoupled by application of a vacuum within the coupler toshrink its diameter.

FIG. 32 illustrates a side view of an embolic implant, in partialbreakaway view, showing a pusher system to detach and deploy theimplant.

DETAILED DESCRIPTION OF THE INVENTIONS

FIGS. 1 and 2 show the vasculature of the brain in sufficient detail toillustrate the use of the embolic implants shown in the followingillustrations. The embolic implant 1 is shown in an exemplary placement.The embolic implant is delivered to this site of a vascular defect withthe delivery catheter 2. The neuro-vasculature, which is the intendedenvironment of use for the embolic implant, supplies the brain 3 withblood through the carotid and the vertebral arteries on each side of theneck. The important arteries include the common carotid artery 4 in theneck, which will be the most common access pathway for the embolicimplants, and the internal carotid artery 5 which supplies theophthalmic artery 6. The external carotid 7 supplies the maxillaryartery 8, the middle meningeal artery 9, and the superficial temporalarteries 10 (frontal) and 11 (parietal). The vertebral artery 12supplies the basilar artery 13 and the cerebral arteries including theposterior cerebral artery 14 and the circle of Willis indicatedgenerally at 15. The siphon 12 a of the vertebral artery appears in theintra-cranial vasculature on the vertebral approach to the Circle ofWillis. Also supplied by the internal carotid artery are the anteriorcerebral artery 16 and the middle cerebral artery 17, as well as thecircle of Willis, including the posterior communicating artery 18 andthe anterior communicating artery 19. The siphon 5 a of the internalcarotid artery 5 appears in the intra-cranial vasculature on the carotidapproach into the Circle of Willis. These arteries typically have aninternal diameter of about 1 mm to 5 mm, most commonly from 2-4 mm. Themethods and devices described herein allow access to these arteries andplacement of a stent in these arteries. In FIG. 1 , the insertioncatheter and an embolic implant 1 are shown threaded through the commoncarotid artery 4 and the internal carotid artery 5, with the embolicimplant disposed within the anterior cerebral artery 16.

FIG. 2 shows the same blood vessels in a schematic view that betterillustrates the Circle of Willis and the arteries which supply thisimportant anatomic feature. The Circle of Willis 15 is a ring ofarteries connecting the internal carotid arteries and the basilar artery(and hence the left and right vertebral arteries) to the anteriorcerebral arteries 16, middle cerebral arteries 17 and posterior cerebralarteries 14. The system provides a redundant supply of blood to thecerebral arteries. The carotid siphon 5 a, which forms an integral partof the internal carotid artery 5, is more clearly visible in this view.Aneurysms, fistulas, AVM's and tumors occurring inside the brain, in theintracranial portion of the carotid arteries, vertebral arteries (andthe portions of those arteries distal to the siphons) and basilarartery, in the circle of Willis or even deeper within the brain may betreated with the embolic implants and delivery systems described below.FIG. 2 shows an exemplary use in which a delivery catheter 2 is insertedthrough the aorta into the common carotid to the internal carotid totreat an vascular defect 20 (a fusiform aneurysm, in this case) with aembolic implants. One implant is deposited distal to the defect to blockretrograde blood flow coming from the Circle of Willis, and one implantis deposited proximal to the defect to block normal blood flow from theinternal carotid artery. Sacrifice of this parent artery isolates thedefect, but the neuro-vasculature on this side of the brain will besupplied the redundant route through the Circle of Willis. It should beappreciated, however, that any thrombus thrown off from the embolicimplant due to delay in stopping normally directed blood flow mightresult in blockage of downstream arteries.

FIG. 3 illustrates an embolic implant, or parent artery occlusiondevice, suitable for use in the neuro-vasculature of a patient. Theembolic implant 21 is wire-frame structure with an overall tubularshape, with struts converging to the longitudinal center (the long axis)of the device where they are bound together with rings. The wire framestructure is partially covered with a membrane. The wire-frame structureis formed by laser-cutting a nitinol tube. The resultant segments of thewire-frame structure include a first zig-zag segment 22 and a secondzig-zag segment 23, with V-shaped elements 24 joined at the “open” endof the V, through small longitudinal struts 25. These struts arelongitudinally offset from each other, so that the embolic implant canbe compressed into a small diameter configuration in which the strutsand the junctions between the zig-zag segments can be compressed tosmaller diameter than would be possible if the struts werelongitudinally aligned. The struts can be compressed into a diametersmaller than the original tube from which the device is cut. Eachzig-zag segment is characterized by vertices 26 of each V-shaped elementwhich point longitudinally away from the longitudinal center of thedevice. From the vertices of the V-shaped elements, end struts 27 extendlongitudinally away from the longitudinal center of the device, andcurve inwardly toward the radial center of the device. The proximalserpentine struts continue into a segment of straight struts 28 (seeFIG. 4 ). The distal serpentine struts continue into a segment ofstraight struts 37 (see FIG. 4 ). The ends of the end struts furthestfrom the longitudinal center are secured in small rings 29 and 30. (Therings are made of a radiopaque material, such as gold, platinum alloys,etc., to help facilitate placement of the embolic implant underfluoroscopic guidance.) The device can be characterized by a proximalend 31 and a distal end 32, defined in reference to the deliverycatheter used to implant the device, and the pathway along which theimplant is navigated to reach the implant site. At the proximal end, thewire frame structure is joined to a delivery rod 33 through anelectrolytic detachment joint 34. The electrolytic detachment joint isheated to break the joint by applying current from a power source at theproximal end of delivery rod. (The electrolytic detachment joint isbroken when low current is applied to it to elicit an electro-chemicalreaction.) (Also, any of the detachment means described below may beused to hold the embolic implant during delivery and detach it from thedelivery rod.)

FIG. 4 illustrates the wire frame structure, as if unrolled, toillustrate its several segments. The first and second zig-zag segments22 and 23 are connected through small central struts 25. Thecircumferential line marked as item 35 is shown to illustrate thelongitudinal displacement of the struts relative to each other. Becausethe struts and the V vertices are not aligned along the samecircumferential line, the implant can be compacted without being limitedby interfering contact of the struts. The serpentine struts extendinglongitudinally from the zig-zag segments connect to scrap zig-zagsegments 36. These segments are formed during the laser cutting process,and are used to facilitate gathering of the serpentine struts into therings at either end of the device. After the serpentine struts aresecured in the rings, these portions are removed and discarded. Asindicated in FIG. 4 , the central zig-zag segments are joined togetherto form several diamond shaped cells with longitudinally displacedvertices, referring both to the longitudinally pointing vertices and thecircumferential vertices. The combined zig-zag segments span 0.180″along the longitudinal axis of the device. The serpentine struts span0.230″.

The wire-frame structure is preferably made of superelastic alloy,formulated to be superelastic at body temperature, such that the implantis self-expanding upon release from its delivery catheter. It may alsobe made of resilient metals or polymers, or shape memory alloy or shapememory polymers. The zig-zag segments are illustrated with sharplydefined V-shaped elements, which assists in compacting the device. TheV-shaped elements can be replaced with U-shaped elements, orsinusoidally curved elements, to create a serpentine segments which arejoined together and the serpentine struts joined to the bottom of theU-shaped elements.

Referring again to FIG. 3 , the wire-frame structure of the embolicimplant is covered with a membrane 38. The membrane 38 covers theproximal end of the embolic implant, from the ring 30 to thelongitudinal center of the implant, and, as illustrated, extending overboth zig-zag segments. The membrane is made of ePTFE and is glued to themetal struts of the wire-frame structure with suitable adhesive. Thismembrane is impermeable to blood on the proximal facing surface 39, andmay also be impermeable on the circumferential surface which covers thecenter of the device. However, as illustrated, the circumferentialsurface of the membrane, which will be pressed against the wall of thevessel at the implant site, may be perforated with perforations or “weepholes” 40. These perforations will facilitate purging the device of airjust prior to implantation. Weep holes may also be provided in theproximal-facing surface of the membrane, if it beneficial to permit somesmall seepage of blood past the membrane.

The membrane, as illustrated, is made of two 0.0003″ (0.00762 mm) thicksheets of ePTFE with a layer of adhesive, such as Bacon Adhesive 430 or431, sandwiched between the two ePTFE sheets such that the ePTFE isimpregnated with the adhesive. The membrane material is prepared byapplying the adhesive to one sheet, and scraping or pressing theadhesive away, leaving the sheet wetted with a thin layer of adhesive onthe surface of the sheet and leaving adhesive impressed into the poresof the ePTFE. The second sheet is then disposed over the wetted surface,that this assembly is then scraped and pressed to flatten the assembly.The result is a sheet of ePTFE which can be glued to the metal struts ofthe wire-frame structure, despite the normal resistance of ePTFE toadhesion. Tantalum powder may be mixed into the adhesive to provide somedegree of radiopacity to the completed membrane. The sheet is thenformed into the roughly conical shape shown, stretched over a conicalmandrel, and heated then peeled off the mandrel. It is then glued orotherwise affixed to the expanded wire-frame structure. The membrane canalso be formed of a single layer of ePTFE which is stretched andheat-formed to match the outer circumference of the expanded wire-framestructure.

The embolic implant may be fashioned so that it opens to a fullyexpanded, unrestrained diameter of 5 mm at its center, but can becompacted to a diameter of less than 1 mm, and preferably to a diameterof about 0.5 mm to fit in a delivery catheter with an internal diameterof 0.021″ (0.5334 mm) or less and outer diameter of 0.0.039″ (1 mm) (3F) or less. This permits far greater access than a comparable Amplatzer™PAO device. An Amplatzer™ at 6 mm in expanded diameter when fullycompacted for delivery, requires a 5 to 6 F (1.7 mm to 2 mm) deliverycatheter with an internal diameter of 0.054″ to 0.072″ (1.37 mm to 1.83mm).

The embolic implant can be coated to enhance thrombogenicity orspace-filling characteristics within its structure. Coatings can includehydrophilic hydrogel or expandable foam which is applied to the implant100 and dried prior to use. Upon exposure to blood or other liquid, thehydrogel or foam absorbs water and swells in volume. Such volumeswelling can increase the hydrogel or foam layer thickness up to tentimes, or more. The hydrophilic hydrogel can comprise fibrin glue,prothrombin, or other blood clotting substance. Thrombogenic (bloodclotting) chemicals can be applied to the embolic implant with orwithout the hydrogel.

In use, a vascular surgeon (typically an interventional radiologist)inserts the embolic implant, packed in a delivery catheter, to a segmentof the cerebral artery (or vein) with a defect. This will typically beaccomplished through a guide catheter, which the surgeon will insertprior to inserting the delivery catheter. After confirming the locationof the device (under fluoroscopy), the surgeon withdraws the deliverycatheter to expose and release the embolic implant. The embolic implantmay be drawn back into the delivery catheter and repositioned ifnecessary (via the delivery wire). When the embolic implant is properlypositioned and deployed from the delivery catheter, the surgeon operatesa small power supply to deliver electric current through a conductorrunning from the detachment joint to the power supply (the pushrod mayserve as the conductor) to melt or electrolytically sever the joint anddetach the embolic implant from the pushrod. A single implant can beused to isolate blood vessels that are not exposed to redundant bloodsupply or retrograde flow. For blood vessels subject to redundant bloodsupply, such as the internal carotid arteries, the surgeon will place afirst implant distal to the defect to prevent retrograde flow and asecond implant to prevent antegrade flow. Additionally, the embolicimplant can be used to temporarily occlude a blood vessel, and theentire system used as a drug or other therapeutic agent delivery device,where the implant is delivered out the end of the catheter and expandedto occlude the blood vessel, after which drugs or therapeutic agents aredelivered from the delivery catheter, the guide catheter or anadditional catheter, just proximal to the embolic device, allowing thetherapeutic agents to be released to the vascular target more precisely.In this case, the implant maintained securely on the delivery rod, andis not detached, but is removed from the vasculature after the deliveryof the agents.

In the same manner, the system can be used for test occlusion. This is adiagnostic technique in which the surgeon temporarily deploys theembolic device, without detaching it from the delivery rod, to occludeblood flow to a suspected segment in the cerebral vasculature to testthe segment and ensure that any defects in that segment are the cause ofsymptoms observed in the patient. If the observed symptoms areameliorated by the test occlusion, the surgeon may, depending on defectshape, size and location, remove the embolic implant from the suspectedsegment and withdraw the delivery catheter from the cerebralvasculature, and then proceed to treat the defect with coils, stents,embolic substances, etc. to preserve the patency of the blood vesselthat has been tested. If, on the other hand, the defect shape, size andlocation are such that the segment should be sacrificed and occluded,the surgeon may detach the embolic implant from the delivery rod toocclude the segment. Because the embolic implant of FIG. 3 and theremaining Figures provides for immediate but easily reversibleocclusion, it is uniquely suited for test occlusion. The system can alsobe used for pre-operative de-vascularization, as an adjunct to surgicalresection of arterio-venous malformations (AVM's) and tumors. In amethod, a surgeon, prior to surgically resecting an AVM or tumor in thebrain, implants one or more embolic devices in arteries supplying bloodto the AVM or tumor, and may also implant one or more embolic devices inveins returning blood from the AVM or tumor, and thereafter resect theAVM or tumor in an open surgery. With this method, bleeding can begreatly diminished when the AVM or tumor is cut from the body. Becausethe embolic implant of FIG. 3 and the remaining Figures provides forimmediate but easily reversible occlusion, it is uniquely suited forpre-operative de-vascularization.

The embolic implant can be configured in various embodiments. FIG. 5illustrates a side view of an embolic implant 100, in its first, smalldiameter, unexpanded state, comprising a proximal end 110, a distal end102, a plurality of longitudinally oriented struts 104, and a pluralityof longitudinally oriented slots. The plurality of longitudinal struts104 are affixed, or integral to, to the proximal band 111 and to thedistal band 103. The plurality of longitudinal slots 106 can befenestrations in the implant such that the remaining structure comprisesthe plurality of struts 104. The locking feature 108 can be affixed, orintegral to, the proximal end 110, the distal end 102, or both. Thelocking feature 108 can comprise a fenestration in the proximal end 110,as illustrated, or it can comprise a structure radially projectingeither outward or inward from the axis of the implant 100. The lockingfeatures 108 can comprise any shape such as circular, rectangular (asillustrated), linear, circumferential, or the like.

FIG. 6 illustrates a side view of the implant 100 with its struts 104expanded to their second, enlarged configuration. The implant 100comprises the proximal band 111, the distal band 103, the plurality ofstruts 104, the plurality of slots 106, and the latch element 108. Thestruts 104 have expanded to form an arcuate shape and then curving backinto alignment with the longitudinal axis of the implant 100 at thepoint where they are affixed to the proximal band 111 and the distalband 103. There are four struts 104 and four slots 106. The strut 104 inthe background is hidden by the strut 104 in front. The top and bottomstruts 104 are visible. The diameter of the expanded implant 100,measured at the center of the struts 104 is approximately 3 mm. More orless expansion can be achieved depending on the length of the struts 104and the amount of strain applied to the struts 104. It is beneficial tokeep the amount of strain within the linear range for the material usedin fabricating the struts 104. The slots 106 become distorted andenlarge significantly for the expanded configuration of the implant 100.By increasing the number of struts 104 and slots 106, greater fill canbe achieved. Greater numbers of struts 104 can be achieved by making thestruts 104 narrower, the slots 106 narrower, or both. It is possible toachieve up to eight, ten, or even twelve struts in a 1 mm diameterunexpanded implant 100. Even higher numbers of struts 104 are achievableif the struts 104 are fabricated from small diameter, round, orrectangular, wire affixed to the ends 110 and 102.

FIG. 7 illustrates a side view of the implant 100 loaded onto a deliverycatheter tube 210 and slidably movable within a guide catheter tube 204,the latter of which is shown in cross-section. The delivery cathetertube 210 is comprised by a delivery catheter 200 and is slidablydisposed over a guidewire 206 which is routed through a lumen of thecatheter tube 210. The implant 100 comprises the plurality of struts104, the distal end 102, the proximal end 110, and the latch feature108. The delivery catheter 200 further comprises a releasable lock 202.

Referring to FIGS. 7 and 8 , the catheter tube 210 is slidably movablewithin the central lumen 112 of the implant 100. The guidewire 206 isslidably movable within a lumen (not shown) of the catheter tube 210 andprojects beyond the distal end of the catheter tube 210. The lockingmechanism 202, affixed to the catheter tube 210 projects outward throughthe latch feature 108 comprised by the proximal end 110 of the implant100. The implant struts 104 are spring metal such as superelasticnitinol and are biased outward to form a curve or arc whenunconstrained. The struts 104, however, are constrained by the wall ofthe guide catheter 204 through which the implant 100 is being advanced.Thus the struts 104 are compressed or collapsed into their first, lowprofile configuration or shape.

FIG. 8 illustrates a side view of the implant 100 having been advancedout the distal end of the guide catheter tube 204. The implant 100comprises the struts 104, the distal end 102, the proximal end 110, andthe latch feature 108. The delivery catheter 200 comprises the deliverycatheter tube 210 and the locking mechanism 202. The guidewire 206 isdisposed within the lumen of the catheter tube 210 and projects out thedistal end thereof. The struts 104 have expanded radially (outwardly inrelation to the longitudinal axis of the implant 100). The expandedstruts 104 form an arc shape but the shape could be triangular,rectangular, trapezoidal, or the like. The struts, possessspring-characteristics and resiliently expand once the constraint of theguide catheter tube 204 has been removed. The proximal end 110 of theimplant 100 is fixed relative to the catheter tube 210 by the lockingmechanism 202 still being engaged with the latch feature 108. The distalend 102 of the implant 100 slides longitudinally proximally over thecatheter tubing 210 and is now further from the distal end of thecatheter tubing 210 than when the implant 100 is in the unexpandedstate, since the distal end 102 moves closer to the proximal end 110 tofacilitate the lateral expansion of the struts 104. The implant 100remains affixed to the delivery catheter 200 until a user operated arelease mechanism from the proximal end of the delivery catheter 200.

FIG. 9 illustrates a side view of the implant 100, the delivery catheter200, and the guide catheter tube 204. The delivery catheter 200comprises the delivery catheter tube and the locking mechanism 202. Theimplant 100 comprises the plurality of struts 104, the distal end 102,the proximal end 110, and the latch feature 108. The guide catheter tube204 comprises a central lumen 302.

Referring to FIGS. 9 and 8 , the guidewire 206 has been removed from thelumen of the delivery catheter tube 210. Removal of the guidewire hascaused the locking mechanism 202 to retract radially inward anddisengage with the latching feature 108 on the implant 100. The proximalend 110 of the implant 100 is still positioned within the lumen 302 ofthe guide catheter tubing 204.

FIG. 10 illustrates a side view of the implant 100, the deliverycatheter 200 and the guide catheter tube 204. The guide catheter tube204 comprises the central lumen 302. The implant 100 comprises thedistal end 102, the plurality of struts 104, the proximal end 110, andthe latch feature 108. The delivery catheter 200 has been withdrawnproximally out of the lumen of the implant 100 and is being withdrawnout of the guide catheter tube 204. Since the lock 202 on the deliverycatheter 200 was released, it no longer prevents relative longitudinalmovement between the catheter tube 210 and the implant 100. The proximalend 110 of the implant remains within the lumen 302 of the guidecatheter tubing 204. However, proximal withdrawal of the guide cathetertube 204 will completely disengage the implant 100 from the guidecatheter tube 204 leaving the implant within the vessel to embolize,thrombose, and occlude the vessel.

FIG. 11 illustrates a side partial breakaway view of the implant 100,the delivery catheter tube 210, the guide catheter tube 204, and theguidewire 206 of FIG. 8 but rotated 90 degrees out of the plane of thepage to permit a side view of the workings of the releasable lock 202and the latch feature 108. The delivery catheter tube 210 furthercomprises the releasable lock 202, the lock spring 404, and the lockopening 402. The implant 100 further comprises the distal end 102, theplurality of struts 104, the proximal end 110, a radiopaque marker 410,and the latch feature 108. The guidewire 206 extends through a lumen 406of the delivery catheter tube 210. The guidewire 206 fills a substantialportion of the catheter lumen 406 and forces the lock spring to becomecompressed radially outward forcing the releasable lock 202 to be forcedoutward through the latch opening 404 in the catheter tube 204. Thereleasable lock 202 is forced outward and engages within the latchfeature 108 on the implant 100 preventing the implant 100 from movingeither proximally or distally relative to the catheter tube 210. Theimplant 100 is constrained and cannot move radially, in a substantial,or functionally meaningful, amount relative to the delivery cathetertube 210 since it is slidably movably disposed over the deliverycatheter tube 210. The latch feature 108 can be located on the proximalend 110, the distal end 102, or both, of the implant 100.

The cross-section of the catheter wall is illustrated with a cross-hatchand can comprise a braid or coil reinforcement of metal, such as but notlimited to, stainless steel, titanium, nitinol, or the like, or polymer,such as polyethylene naphthalate (PEN), PET or the like, embedded withina polymeric surround. The releasable lock 202 is affixed to a first endof the lock spring 404. The lock spring 404, which is illustrated as acantilever spring, is affixed at a second end to the catheter tubing210. The lock spring 404 can be fabricated from metals such as, but notlimited to, nitinol, stainless steel, titanium, cobalt nickel alloy, orthe like. The lock spring 404 can also be fabricated from polymers suchas, but not limited to, PEEK, PEN, PET, polycarbonate, and the like. Thelock spring 404 can be affixed to the catheter tube 210 using adhesives,fasteners, heat welding, ultrasonic welding, and the like.

FIG. 12 illustrates a side view of the implant 100 and its deliverysystem of FIG. 11 but with the guidewire 206 having been withdrawnproximally and removed from inside the implant 100. The lock spring 404has returned to its unrestrained position and has withdrawn thereleasable lock 202 to a position inside the lock opening 402 such thatthe releasable lock 202 no longer engages with the latch feature 108 onthe implant 100. Thus, the implant 100 is now free to movelongitudinally along the delivery catheter tubing 210.

The releasable lock 202 may also be operated by a separate linkage (notshown) disposed through the central lumen coaxially around the guidewireor through a separate lumen. The linkage can be configured to pull,push, or rotate such that the releasable lock 202 can be moved radiallyinward and outward. The rotational linkage can turn a jackscrew or wormgear to move the lock 202 inward and outward. An electrically poweredactuator (not shown) can be used to lock and unlock the catheter tubing210 from the implant 100. The implant 100 can be released from thecatheter tubing 210 by means of a fluidic system operably configured toprovide either positive or negative pressure to drive the implant off ofthe catheter or disengage the releasable lock 202. Ohmic or resistiveheating can be used to move a shape memory or heat-reactive material toforce disengagement between the implant 100 and the catheter tubing 210.

FIG. 13 illustrates a side view of an implant 700 having been releasedfrom the delivery catheter tube 210 but still residing proximate theguide catheter tube 204, which is shown in cross-section. The implant700 comprises the distal end 102, the plurality of struts 104, theproximal end 110, a covering 702, and a proximal covering bond 704. Thecovering 702 is affixed to the proximal end 110 by the bond 704. Thecovering 702 can be elastomeric and be resiliently biased against thestruts 104 or it can be adhered thereto.

FIG. 14 illustrates a side view of an implant 750 comprising the distalend 102, the plurality of struts 104, the proximal end 110, a covering752, a proximal covering bond 754, and a distal covering bond 756. Theimplant 750 has been released from the delivery catheter 210 and itsproximal end resides still partially within the distal end of the guidecatheter tube 204. The proximal end 110, the struts 104, and the distalend 102 are similar to the implant 700 of FIG. 7A. The covering 752, asillustrated, comprises a mesh or fabric. The covering 752 can comprisestructures such as, but not limited to, a weave, a braid, a knit, amembrane with macroscopic holes or pores, and the like. The covering 752surrounds substantially all, or 100% of the surface of the implant 750.The proximal end 110 can project out from underneath the covering 752 topromote or facilitate engagement and fixation to the delivery cathetertube 210.

FIG. 15 illustrates a side view of an expanded embolic implant 800having just been released from its delivery catheter 210 and stillproximate the guide catheter tube 204, which is illustrated incross-section. The implant 800 comprises a distal end 802, a pluralityof struts 104, a proximal end 110, and a plurality of gaps 106. Thestruts 104 are integral to, or affixed to, the proximal end 110, whichis configured as a short cylinder. The plurality of struts 104 areaffixed to each other at the distal end 802. There is substantially nodistal projection beyond where the struts 104 are affixed to each other.This implant design 800 is suitable for placement in an aneurysm withinthe cerebrovasculature. Berry aneurysms are configured such that thedistal end 802 can be inserted into the aneurysm and the implant can bereleased from the delivery catheter at that point. The unitary structureof the struts 104 can also be comprised by the proximal end 110.

FIG. 16 illustrates a view of the implant 800 of FIG. 8A as seen lookingtoward the distal end 802. The implant 800 comprises the plurality ofstruts 104, the proximal end 110, the distal end 802, the plurality ofgaps 106, and an indexing hole 804. The implant 800 is configured so asto be smooth and unsharp in the distal end 802 such that the distal end802 can be inserted into a cerebrovascular aneurysm and deployed thereinwithout causing trauma to the fragile tissues of the aneurysm. Theindexing hole 804 can be engaged by a linkage or rod (not shown)disposed within the lumen of the delivery catheter, and configured formanipulation at the proximal end of the delivery catheter, to move thedistal end of the implant 800 away from the proximal end 110, stretchingthe implant 800 longitudinally, and causing the struts 104 to collapseradially during placement. Removal of the linkage or rod can cause thestruts 104 to assume their arcuate shape and expand. Referring to FIGS.11 and 12 , the linkage or rod can replace the guidewire 206 for thepurposes of engaging and disengaging the releasable locking mechanism202 from the latch feature 108 of the implant 800. The implant 800 cancomprise between 2 and 20 struts 104 and can further comprise coverings702 and 752 as illustrated in FIGS. 13 and 14 . The implant 800 can beconstructed from flat metal that is cut with the struts 104 formed intoa star pattern, then bent around and affixed to the proximal end 110 bywelding, fasteners, adhesives, or other fixation technique.

FIG. 17 illustrates a side view of an expanded embolic implant 900comprising a plurality of longitudinal struts 104, a proximal end 110, adistal end 102, a lock window 108 and a membrane covering 902. Theimplant 900 is releasably affixed to a delivery catheter 210 furthercomprising a releasable lock 202. The delivery catheter 210 is disposedover a guidewire 206 running through a delivery catheter 210 centrallumen (not shown) while the delivery catheter 210 is inserted through aguide catheter or sheath 204 further comprising a guide catheter lumen302. The delivery catheter 210 is routed through the open central lumen(not shown) of the proximal end 110 and the distal end 102 of theimplant 902 to project distally of the distal end 102. The guidewire 206projects out the distal end of the delivery catheter 210 and resideswithin a central lumen (not shown) comprised by the delivery catheter210. The embolic implant 900 has been exposed outside the lumen 302 ofthe introducer sheath or guide catheter 204 and is unconstrained suchthat diametric expansion is possible. The longitudinal slats 104 aregenerally compressed prior to this expansion and aligned substantiallyaxially or longitudinally with respect to the catheter 210. Onceexpanded, as illustrated, the ribs or slats 104 are biased to formarcuate shapes near the proximal end 110 and the distal end 102. Thecentral region of the ribs or slats 104 remains generally straight andaligned longitudinally. The proximal region of the slats 104 is coveredwith a membrane 902. The membrane 902 can cover the distal end of theslats 104 and not the proximal end. The membrane 902 can cover both theproximal end and the distal end. The membrane 902 can cover the entireregion of the implant 900 which is comprised by the slats 104. Themembrane 902 can be fabricated from materials described within thisdocument.

FIG. 18 illustrates a side view of a diametrically expanded embolicimplant 950 still attached to its delivery catheter 210. The sheath 204of FIG. 17 has been removed. The embolic implant 950 comprises theproximal end 110, the distal end 102, a locking window 108, a pluralityof longitudinally projecting bars or struts 104, and a plurality ofpartial longitudinally projecting bars or struts 904 affixed only to theproximal end 110. The embolic implant 950 further comprises a membrane902 covering the proximal portion of the embolic implant 950. Thecatheter 210 further comprises the releasable lock 202, a guidewirelumen (not shown), and a guidewire 206. The partial struts, ribs orslats 904 affixed to the proximal end 110 of the implant 950 projectsubstantially to the center of the implant 950 but they can extendwithin any range from about 10% to 90% of the way to the distal end 102.The partial struts 904 can be affixed to the distal end 102 and beunconnected from the proximal end 110 with the same amount of projectionin the opposite direction as described for partial struts 904 affixed tothe proximal end 110. The implant 950 can comprise the membrane 902,optionally disposed over the proximal end and extending substantiallythe length of the partial struts 904. Full length struts 104 providestructural control over the overall diameter and length of the implant950. The partial struts 904 can project substantially the same radialdistance outward as the full length struts 104, or they can projectfurther radially, or they can project less far, radially, than the fulllength struts 104. The full length struts 104 and the partial struts 904can comprise the same materials, or they can comprise differentmaterials or the same materials but with different properties.

FIG. 19 illustrates a side view of a radially collapsed embolic implant1000. The implant 1000 comprises the proximal end 110, the distal end102, the lock window 108, and the mesh 1002. The implant 1000 systemalso comprises the delivery catheter 210 further comprising thereleasable lock 202, the guidewire lumen (not shown) and the guidewire206. The implant 1000 system further comprises a delivery sheath orguide catheter 204, which is shown in cross-section. The mesh 1002 isconstrained radially within the lumen 302 of the guide catheter ordelivery introducer 204. The proximal end 110 of the implant 1000remains affixed to the delivery catheter 210 by way of the lock 202 onthe delivery catheter 210 being engaged into the locking feature 108,which is a rectangular opening in the proximal end 110. The guidewire206 is illustrated as remaining in place, which is generally the case,and is used to assist guiding the delivery catheter 210 through thevasculature to the target treatment area.

FIG. 20 illustrates a side view of the embolic implant 1000 from FIG. 19following radial expansion. The embolic implant 1000 comprises the mesh1002, the proximal end 110, the distal end 102, and the proximal lockwindow 108. The embolic implant 1000 system also comprises the sheath204, the delivery catheter 210 further comprising the guidewire lumen(not shown), the releasable lock 202, and the guidewire 206. The mesh1002 of the embolic implant 1000 has expanded to its full operationaldiameter. The mesh 1002 can comprise a self-expanding, spring biasedmaterial, it can comprise a malleable, balloon expandable material, amalleable material that is diametrically expanded by axial compressionof the distal end 102 toward the proximal end 110, it can comprise shapememory materials that are activated at body temperature, shape memorymaterials that are activated by Ohmic heating to temperatures above bodytemperature, it can comprise materials that exist or transition into asuperelastic or pseudoelastic state, or the like. The mesh 1002 cancomprise wires of round, rectangular, oval, triangular, or othergeometric cross-section. The expanded mesh 1002 can comprise an outerdiameter of between about 1.1 and 10 times that of the collapsed implant1000 of FIG. 19 . The sheath 204 is shown retracted to expose theproximal end 110. The delivery catheter 210 remains affixed to theimplant 1000 by way of the releasable lock 202, which is affixed to thedelivery catheter 210, being engaged into the locking feature 108 on theproximal end 110. The guidewire 206 remains in place within the lumen(not shown) of the delivery catheter 210.

FIG. 21 illustrates a side view of a diametrically expanded embolicimplant 1100 alone without any of its associated delivery catheters orsheaths, which are the same as those described herein for otherembodiments. The expanded embolic implant 1100 comprises the proximalend 110, the distal end 102, a plurality of longitudinally oriented barsor stays 1102, the locking feature 108, and a plurality of serpentinecentral regions on the longitudinal bars or stays 1102. The longitudinalstruts 1102 are affixed or integral to the proximal end 110 and thedistal end 102. The longitudinal struts 1102 are formed integrally with,or affixed to, the serpentine central strut area 1104. The serpentinecentral strut area 1104 can comprise a single undulation, or a pluralityof undulations ranging from about 1 to about 20 undulations. In theillustrated embodiment, a total of 8 struts are present. The lockingfeature 108 can be integrally formed with the proximal end 110, thedistal end 102, or both. The locking feature 108 can comprise structuresother than a window in generally cylindrical thin walled structures suchas is illustrated herein. Such other locking features 108 can compriseprojections, wells, fasteners, bayonet mounts, friction interference,and the like.

FIG. 22 illustrates a side view of a diametrically expanded embolicimplant 1150. The embolic implant 1150 further comprises the proximalend 110, the distal end 102, the locking feature 108 a plurality ofproximal longitudinally oriented struts or stays 1154, and a distal mesh1156, and a connecting region 1152 between the struts 1154 and the mesh1156 elements. The longitudinal struts 1154 are affixed, or integral to,the proximal end 110. The distal mesh 1156 is affixed, or integral to,the distal end 102. The longitudinal struts 1154 are affixed to the mesh1156 at a plurality of connector points 1152 which can be welded,fastened, or formed integrally with the mesh 1156 and the struts 1154.The mesh 1152 is illustrated as occupying approximately ½ of thedistance between the proximal end 110 and the distal end 102 but itcould occupy anywhere between 10% and 90% of the distance. The mesh 1156can be at the distal end, as illustrated, or it can be at the proximalend.

FIG. 23 illustrates a side view of an expanded embolic implant 1200comprising the proximal end 110 further comprising the locking feature108, the distal end 102, a plurality of distal longitudinally projectingstruts or bars 1204, a plurality of thinner, proximal longitudinallyprojecting struts or bars 1208, 1206, 1202 affixed to the proximal endand to a connector point 1210 at the proximal end of the distal struts1204. The longitudinal struts in the distal end 1204 are larger than thestruts 1202, 1206, and 1208 in the proximal end, but they can also beapproximately the same cross-section or smaller in size. The largerdistal struts 1204 are affixed, or integral to, the smaller proximalstruts 1202, 1206, 1208 in the connection zone 1210. As illustratedthere are three small proximal struts 1202, 1206, and 1208 for eachlarger distal strut 1204. The number of proximal struts can range fromone to about 5 or more for each distal strut 1204. The orientation canalso be reversed such that the smaller number of larger struts 1204 areaffixed or integral to the proximal end with the smaller struts, ofgreater plurality, are affixed to the distal end.

FIG. 24 illustrates a side view of a laterally expanded embolic implant1250 comprising the proximal end 110 further comprising the lockingfeature 108, the distal end 102, a proximal lobe 1252 comprising aplurality of struts 1258, and a distal lobe 1254 comprising a pluralityof longitudinally disposed struts 1258. The proximal lobe 1252 and thedistal lobe 1254 are affixed to each other in the central connectorregion 1256. The longitudinal struts 1252 in the proximal region areaffixed to, or integral with, the longitudinal struts in the distalregion 1254. The proximal struts 1252 and the distal struts 1254 can beaffixed or integral to each other at the connection zone 1256 or at anyother convenient location. As illustrated the connection zone 1256 isconfigured to a smaller diameter than the maximum diameter of theproximal lobe 1252 or the distal lobe 1254. The maximum diameter of theproximal lobe 1252 can be greater than that of the distal lobe 1254, itcan be smaller, or it can be approximately the same. The strutscomprising the proximal lobe 1252 and the distal lobe 1254 can be thesame struts. The struts comprising the proximal lobe 1252 and the distallobe 1254 can be affixed to, or integral with, the proximal end 110 andthe distal end 102, respectively. The distal end 102 can comprise alocking feature 108 similar to that of the proximal end 110.

FIG. 25 illustrates a side view of an expanded embolic implant 1300comprising the proximal end 110 further comprising the locking feature108, the distal end 102, a plurality of proximal longitudinallyprojecting struts or bars 1302 which transition in the central zone to aplurality of complimentary thinner bars or struts 1308 in the distalregion. Interdigitated between the distal longitudinal struts 1308 are aplurality of thin bars 1304 shaped as leaves or flower petals in aclosed loop. The tips 1306 of the flower petals 1304 are configured in atriangular shape and are bent slightly, radially outward. Thelongitudinal struts 1302 are larger in lateral dimension toward theproximal end 110 and smaller in lateral dimension toward the distal end102. Smaller struts 1304, affixed or integral to the distal end 102 areformed into a loop or flower petal shape and project axially onlypartially toward the proximal end 110. The smaller struts 1304 areformed with a triangular end configuration which is bent slightlyoutward to enhance the ability of the implant 1300 to engage with avessel wall, wall thrombus, atheroma, or the like. The triangular tipcan follow the approximate shape of the implant 1300 or it can be bentoutward or inward. The entire flower petal loop 1304 can also beconfigured to have an outward, or inward, projection beyond the generalenvelope of the implant 1300 to assist with stability in the targetimplant site. The flower petal loops 1304 and the distal longitudinalstruts 1308 can have a smaller cross-section than that of the proximallongitudinal struts 1302 and similar to that of the distal longitudinalstruts 1308. The flower petal loops 1304 can have similar or largercross-sections than the proximal longitudinal struts 1302. The flowerpetal loops 1304 can be affixed to the proximal end 110 rather than thedistal end 102.

FIG. 26 illustrates a side view of an expanded embolic implant 1350comprising the proximal end 108 further comprising a locking feature108, the distal end 102, a plurality of longitudinally oriented struts1352, and a plurality of laterally projecting struts 1354. The axiallyoriented struts 1352 can be affixed at their proximal end to theproximal end 110 or they can be formed integrally thereto. At theirdistal end, the axially oriented struts 1352 can be affixed or integralto the distal end 102. The lateral struts 1354 can be integral to theaxial struts 1352 or they can be affixed thereto using fasteners, welds,adhesive bonding, or the like. The lateral struts 1354 can have the samemechanical properties as the longitudinal struts 1352, e.g. shapememory, malleable, spring, or the like. The lateral struts 1354 can havedifferent mechanical properties from those of the longitudinal struts1352. The lateral struts can be straight, as shown, or they can havecurvature or bends to accommodate compression of the space between thelateral struts 1352 when the implant 1350 is collapsed or compressed toits radially small diameter.

The longitudinal struts can comprise superelastic nitinol, while thelateral struts 1354 can comprise shape memory nitinol that retainsmartensitic properties when in the packaged state but which transitionto superelastic properties at temperatures higher than room temperature.Typical temperatures that could generate phase transition fromMartensite to Austenite would include those above room temperatures ofabout 22° C. to 25° C. to about body temperature of about 37° C. orsomewhere therebetween. The illustration of FIG. 26 shows the implant1350 with its lateral struts 1352 straightened but said struts 1352would possess a serpentine, curved, or bent shape with the implant 1350in its diametrically collapsed configuration such as prior to, andduring introduction into the patient. The lateral struts 1354 can benear the proximal end, the distal end (as illustrated), toward, thecenter, or a plurality of lateral struts 1354 can connect thelongitudinal struts 1352 in more than one place.

FIG. 27 illustrates a side view of an expanded embolic implant 1400comprising the proximal end 108 further comprising a locking feature108, the distal end 102 further comprising a distal locking feature1408, a plurality of longitudinally oriented struts 1402 at the proximalend distal ends of the implant 1400, a central mesh 1404, and aplurality of connector regions 1406 wherein the central mesh 1404 isaffixed to the ends of the struts 1402. The longitudinal struts 1402 areaffixed to the proximal end 110 while the longitudinal struts 1402 atthe distal end are affixed to the distal end 102. The proximal lockingfeature 108 is affixed to, or integral with the proximal end 110 whilethe distal locking feature 1408 is affixed to, or integral with thedistal end 102. Both the proximal end 110 and the distal end 102 arehollow, axially elongate structures comprising a central lumen (notshown). The proximal locking feature 108, the distal locking feature1408, or both, can comprise a fenestration in the proximal end 110 andthe distal end 102, respectively. The fenestration can be rectangular(as shown) but it can also be round, oval, triangular, or any othergeometric shape suitable for interconnection with a lock on a deliverycatheter. The locking features 108 and 1408 can further compriseprojections, bumps, threaded regions, quick releases, bayonet mounts,fasteners, or the like.

FIG. 28 illustrates a side cross-section and partial breakaway view ofthe embolic implant 1500 affixed to the distal end of the catheter tube204. The embolic implant 1500 comprises the distal end 102 and theproximal end 1510 further comprising the internal threads 1516. Thedistal end of the catheter tube 204 further comprises a rotating coupler1504, further comprising guidewire engaging projection 1518, a bearingflange 1506, a set of external threads 1502, an internal lumen 1512, anda tapered inlet 1508. The embolic implant 1500 system further comprisesthe delivery sheath, introduction sheath, or guide catheter 204, and adeployment guidewire 1524 further comprising a longitudinal groove 1522and an optional guidewire radiopaque marker 1514. The catheter tube 204further comprises a rotational bearing groove 1520. The implant 1500comprises a plurality of longitudinally oriented slats, bars, runners,or the like 104. The rotating coupler 1504 is affixed, or integral to,the bearing flange, the external threads 1526, and the guidewireengaging projection 1518. The external threads 1502 of the rotatingcoupler 1504 engage with complementary internal threads 1516 on theimplant 1500. Rotation of the rotating coupler 1504 relative to theimplant 1500 causes increased longitudinal engagement or decreasedlongitudinal engagement, depending on the direction of the rotation.

In another embodiment, instead of threads, the rotating coupler 1504 cancomprise a prong or projection (not shown) that engages with acircumferential slot (not shown) on the proximal end 1510 of the implant1500. The prong or projection (not shown) can be comprised by theimplant 1500 while the bayonet groove can be comprised by the distal endof the catheter shaft 204 or the rotating coupler 1504. The rotationalcoupling system can be comprised by the distal end 102 of the implant1500 instead of the proximal end 1510.

A mechanism is provided to prevent rotation of the implant 1500 whilethe rotating coupler 1504 is being twisted. The rotation preventionmechanism can comprise structures and means including, but not limitedto, a friction fit between the implant 1500 and the guide catheter 204,a separate stabilization linkage, operable from the proximal end, thatengages with a hole, groove, or receptacle and locks the implant 1500 toprevent rotation about its longitudinal axis, and the like. The implant1500 can further comprise a projection (not shown) that engages alongitudinal slot (not shown) in the distal end of the guide catheter204 tubing. The projection is capable of axial slidable movement withinthe slot but is constrained against rotational motion by interferencewith the walls of the slot. The guide catheter 204 can comprise theprojection while the implant 1500 can comprise the slot. The guidecatheter 204 can comprise internal runners that project inwardly andengage with the spaces between the longitudinal slats 104 of theunexpanded implant 1500. The implant 1500 can be pushed out of the guidecatheter tube 204 by axial or longitudinal distal movement of thecatheter tubing 210 relative to the guide catheter tube 204.

FIG. 29 illustrates a side, partial breakaway, view of an embolicimplant 1600 comprising a plurality of axially oriented struts 104affixed to the distal end 102 and to the proximal end 1610. The embolicimplant 1600 further comprises the delivery catheter tube 210, the guidecatheter 204, a pusher 1602 further comprising a first electrical lead1604, a second electrical lead 1606, a resistive heating coil 1608, anda fusible link 1612. The fusible link 1612 is affixed, or integral to,the distal end of the pusher 1602. The fusible link 1612 can comprise alow temperature meltable metal such as solder, or a polymer materialsuch as polypropylene, polyethylene, polyester, or the like. The fusiblelink 1612, as illustrated, is affixed to the implant 1600 in the regionof the proximal end 1610 but it can also be affixed to the implant 1600at the distal end 102. The resistive heating element 1608 can comprisematerials such as tungsten, nickel chromium wire, or the like. Theresistive heating element 1608 can be wrapped around the fusible link1612 in the form of a coil, as illustrated, or it can be orientedlongitudinally or in any other configuration in sufficiently closeproximity as to transfer enough heat to melt the fusible link 1612. Itis generally beneficial to shield the body from the heat of theresistive heating element 1608 and that is accomplished by insulationprovided or comprised by the guide catheter tube 204 and the implantproximal end 1610. The pusher 1602 can be used to physically push theimplant 1600 away from the guide catheter 204 to ensure completedeployment and release. The system can further comprise a guidewire 206of FIG. 4 , for example, if desired.

A hydraulically detachable linkage can comprise a fluid channel runningfrom the proximal end of the delivery catheter to the distal end. Thefluid channel can be operably connected to a piston, bladder, expandablemember, or other structure that can force a releasably coupled implantfrom the distal end of the delivery catheter to cause release of theimplant. The fluid channel is preferably pressurized with a liquid suchas saline, radiopaque contrast media, or the like. Pressures of above1,000 PSI can be generated using a small syringe and hand pressureapplied by the operator to a pressurization port at the proximal end ofthe delivery catheter that is operably connected to the fluid channel.Pressures nearing 1,000 PSI or higher can force an implant, frictioncoupled to the distal end of the delivery catheter to becomedisconnected, detached, or otherwise released. The fluid pressure can bedelivered into a space just proximal to the implant such thatpressurization of the space forces the implant to move distally anddisconnect from the delivery catheter. The space is operably connectedto the fluid channel.

FIG. 30 illustrates a side view, in partial breakaway, of an embolicimplant 1700 comprising a distal end 102, a proximal end 1710, and apiston 1702. The system further comprises the guide catheter 204, andthe delivery catheter sheath 210 further comprising the pressurizationlumen 1704. The implant 1700 has expanded to its full expandedoperational diameter and the piston 1702 has just begun moving distallyto separate the implant 1700 from the catheter 210. The piston 1702 isaffixed to the proximal end 1710. The piston 1702 projects axially intothe pressurization lumen 1704 and is slidably constrained to move onlylongitudinally therein. The piston 1702 is fluidically sealed to thewalls of the catheter 210 such that pressure generated within the lumen1704 does not leak out around the piston 1702. Fluid suitable forpressurization of the lumen 1704 can comprise materials such as, but notlimited to, water, radiopaque contrast media, ethanol, and the like. Thefluid is preferably an incompressible fluid so as not to cause pressurestorage within the fluid, the release of which could be damaging to theinstrumentation or the patient. Pressures suitable for pressurization ofthe lumen 1704 can range from about 10 PSI to about 3,000 PSI, all ofwhich can be generated with a hand-held syringe. The higher pressuresare often necessary to overcome the pressure losses within the smalldiameter lumen 1704, which can range from about 0.005 inches to about0.050 inches but generally ranges from about 0.010 to about 0.030 inchesin diameter. The length of the catheter tubing 210 is generally verylong and can range from about 45 cm to about 250 cm with a preferredlength of about 80 cm to about 150 cm for cerebrovascular accessprocedures.

The piston can comprise a bellows structure (not shown) that ensuresthat fluid pressure loss will not occur when the pressurization lumen1704 is pressurized with fluid. The piston 1702 can further comprisepiston rings or seals (not shown) to further inhibit pressure loss whilethe piston is being ejected or expelled from the distal end of thecatheter tube 210. The piston can drive a latch, catch, releasable lock,or other structure that grasps a portion of the implant 1700. By drivingthe latch, the piston can unlock or unlatch the delivery catheter tube210 from the proximal end 1710 of the implant 1700. The implant 1700 canfurther be driven off or separated from the delivery catheter tube 210by distal relative movement of the guide catheter 204 or a separatepusher.

By similar means as that of the hydraulically detachable linkage, avacuum linkage can be used to pull a vacuum at the distal end of thedelivery catheter causing reduction in size or decreased projection of acoupling mechanism configured to releasably hold the implant secured tothe delivery catheter.

FIG. 31 illustrates a side view, in partial breakaway, of an implant1800 comprising a distal end 102, a plurality of struts 104, and aproximal end 1810, further comprising an orifice 1802 and an inner lumen1812. The system further comprises the delivery catheter 210 furthercomprising the pressure lumen 1704, the guide catheter 204, a bladder1804 further comprising a bladder internal volume 1808, and a bladderbond 1806. The bladder 1804 is affixed to the distal end of the deliverycatheter 210 by the bladder bond 1806. The bladder lumen 1808 isoperably connected to the pressurization lumen 1704 and is otherwisefluidically sealed. The bladder 1804 can be constructed in its smallprofile and then be inflated to a diameter larger than that of theorifice 1802 or it can be constructed to be expanded to a diameterlarger than that of the orifice 1802 in its unstressed state.Application of a vacuum or withdrawal of fluid from the bladder lumen1808 by way of the pressurization lumen 1704 can reduce the lateral ordiametric extent of the bladder 1804 to a size smaller than that of theorifice 1802 such that the implant 1800 is decoupled from the deliverycatheter tubing 210. Further separation and deployment can be generatedby distal movement of the guide catheter 204 relative to the deliverycatheter tube 210.

Withdrawal of a vacuum, or removal of liquid or fluid, in the systemdescribed in FIG. 17 can pull the plug 1702 off the implant 1700, thusreleasing and deploying the implant 1700. The plug 1702 can be frictionfit or weakly snapped into a detent in the implant 1700 thus allowingfor removability of the plug 1702, under vacuum applied to thepressurization lumen 1704.

A mechanical pusher can be activated at the proximal end of the deliverycatheter to move axially and force a releasably coupled implant from thedistal end of the delivery catheter. The mechanical pusher is generallydisposed within a lumen of the delivery catheter to be radiallyconstrained but longitudinally movable within the lumen. The mechanicalpusher can be directly pushed or moved axially by way of mechanicaladvantage such as a lever or trigger mechanism. The mechanical pushercan also be rotated to generate a jack-screw effect thus generatinglinear motion at the distal end of the delivery catheter and forcing theimplant to release or decouple.

Coupling of the implant at the distal end of the catheter can comprise asimple friction fit with the implant comprising an outer sleeve thattightly fits over a stub of the delivery catheter. The catheter stubprojects into the sleeve of the implant, for example and is held thereby a press-fit, binding fit, detents and projections, or the like.

FIG. 32 illustrates a side, partial breakaway, view of an implant 1900that is releasably affixed to its delivery catheter tubing 210 by apusher 1902. The implant 1900 comprises the distal end 102, a pluralityof runners 104, a proximal end 1910 further comprising a bumper 1906 andengagement detents 1904. The system further comprises the deliverycatheter tube 210 further comprising one or more projections 1912, oneor more spring elements 1914, and the guide catheter tube 204. Theproximal end 1910 is a substantially hollow, axially elongate structureaffixed to the proximal end of the runners 104. Affixed to the interiorof the proximal end 1910 is a bumper or region of reduced centralopening 1906. Affixed to the distal end of the delivery catheter tube210 are the one or more engagement prongs 1912 biased outward by one ormore optional springs 1914. The engagement prongs 1912 are configured toengage with depressions or detents 1904 on the inside of the implantproximal end 1910. The engagement prongs 1910 cause a defeatableengagement that can be overcome by axial force applied by distalmovement of the pusher 1902 against the bumper 1906. The springs 1914are optional and the same functionality can be obtained from resiliencyin the delivery catheter tube 210 or in the structure of the engagementprongs 1912. The detents 1904 on the inside of the proximal end 1910 canalso be configured as holes or openings in the proximal end 1910 or asserrated or circumferentially grooved surfaces to grip the prongs 1912.

The implants can be affixed to the delivery catheter by magnetic meansthat can activated and deactivated by use of electromagnets powered fromthe proximal end of the delivery catheter 200 using electrical contactssuch as those illustrated in FIG. 16 .

The implant 100, when intended for cerebrovascular embolization, canhave a diameter or lateral, unexpanded dimension of less than 0.021″(0.5334 mm). The implant 100 can have a length of about 0.2 to 0.3inches in its unexpanded state. The wall thickness of the implant canrange from about 0.001 to 0.005 inches. For neuro-interventionalprocedures in the cerebrovasculature, the expanded diameter of theimplant 100 should range from about 2 mm to about 6 mm with a preferredrange of about 3 mm to about 5 mm.

The implant 100 can further comprise coatings to enhance thrombogenicityor space-filling characteristics. Such coatings can comprise hydrophilichydrogel or expandable foam which is applied to the implant 100 prior touse, and be allowed or caused to dry. Upon exposure to blood or otherliquid, the hydrogel or foam absorbs water and swells in volume. Suchvolume swelling can increase the hydrogel or foam layer thickness up toten times, or more. The hydrophilic hydrogel can comprise fibrin glue,prothrombin, or other blood clotting substance, or the blood clottingchemical, substance, or material can be applied to the implant 100without the hydrogel.

While the preferred embodiments of the devices and methods have beendescribed in reference to the environment in which they were developed,they are merely illustrative of the principles of the inventions. Theelements of the various embodiments may be incorporated into each of theother species to obtain the benefits of those elements in combinationwith such other species, and the various beneficial features may beemployed in embodiments alone or in combination with each other. Otherembodiments and configurations may be devised without departing from thespirit of the inventions and the scope of the appended claims.

We claim:
 1. A system comprising: a delivery member; and an embolicimplant comprising: a wire frame structure comprising: a pair ofopposing zigzag segments including a plurality of elements, each elementof the plurality of elements defining an open end and a closed endopposite the open end, and each element of the plurality of elementsbeing joined at the respective open end to another element via struts toform a central portion of the wire frame structure, the closed ends ofthe elements pointing proximally or distally away from a longitudinalcenter of the wire frame structure; a first plurality of longitudinallyoriented struts extending from proximally pointing closed ends of theelements, the first plurality of longitudinally oriented struts beingjoined together at a proximal end of the wire frame structure; and asecond plurality of longitudinally oriented struts extending fromdistally pointing closed ends of the elements, the second plurality oflongitudinally oriented struts being joined together at a distal end ofthe embolic implant; a blood impermeable membrane covering at least apart of the wire frame structure and extending from the proximal end ofthe wire frame structure to at least distal to the longitudinal centerof the wire frame structure; and a detachment joint configured toreleasably join a proximal end of the wire frame structure to thedelivery member.
 2. The system of claim 1, wherein the plurality ofelements comprises V-shaped elements.
 3. The system of claim 1, whereinthe plurality of elements comprises U-shaped elements.
 4. The system ofclaim 1, wherein the plurality of elements comprises sinusoidally curvedelements.
 5. The system of claim 1, wherein the first plurality oflongitudinally oriented struts are joined together near a radial centerof the wire frame structure and the second plurality of longitudinallyoriented struts are joined together near the radial center of the wireframe structure.
 6. The system of claim 1, further comprising: a firstring joining the first plurality of longitudinally oriented strutstogether at the proximal end of the wire frame structure; and a secondring joining the second plurality of longitudinally oriented strutstogether at the distal end of the wire frame structure.
 7. The system ofclaim 1, wherein the struts joining the elements are longitudinallydisplaced from each other.
 8. The system of claim 1, wherein theproximally pointing closed ends of the elements are notcircumferentially aligned.
 9. The system of claim 1, wherein the bloodimpermeable membrane comprises a proximal facing surface and acircumferential facing surface, wherein at least the proximal facingsurface is blood impermeable.
 10. The system of claim 9, wherein theproximal facing surface and the circumferential facing surface are bloodimpermeable.
 11. The system of claim 1, wherein the blood impermeablemembrane is perforated with weep holes.
 12. The system of claim 1,wherein the blood impermeable membrane comprises expandedpolytetrafluoroethylene (ePTFE).
 13. The system of claim 1, wherein thewire-frame structure is at least partially formed from a pseudoelasticmetal alloy.
 14. The system of claim 1, wherein the wire frame structureis configured to expand from a compacted configuration to a fullyexpanded configuration, wherein when the wire frame structure is in thefully expanded configuration, the wire frame structure has a maximumdiameter of about 5 millimeters, and when the wire frame structure is inthe compacted configuration, the wire frame structure has a maximumdiameter of less than about 0.6 mm.
 15. The system of claim 1, whereinthe detachment joint comprises an electrolytic detachment joint.
 16. Thesystem of claim 1, wherein the detachment joint comprises a detentconfigured to engage with the delivery member.
 17. An embolic implantcomprising: a wire frame structure comprising: a pair of opposing zigzagsegments including a plurality of elements, each element of theplurality of elements defining an open end and being joined at therespective open end to another element via struts to form a centralportion of the wire frame structure, the elements defining proximal ordistal vertices pointing proximally or distally away from a longitudinalcenter of the wire frame structure; a first plurality of longitudinallyoriented struts extending from the proximally pointing vertices of theelements, the first plurality of longitudinally oriented struts beingjoined together at a proximal end of the wire frame structure; and asecond plurality of longitudinally oriented struts extending from thedistally pointing vertices of the elements, the second plurality oflongitudinally oriented struts being joined together at a distal end ofthe embolic implant; and a blood impermeable membrane covering at leasta part of the wire frame structure extending from the proximal end ofthe wire frame structure to at least distal to the longitudinal centerof the wire frame structure; and a detachment joint configured toreleasably join a proximal end of the wire frame structure to a deliverymember.
 18. The embolic implant of claim 17, wherein the plurality ofelements comprises V-shaped elements.
 19. The embolic implant of claim17, wherein the plurality of elements comprises U-shaped elements. 20.The embolic implant of claim 17, wherein the plurality of elementscomprises sinusoidally curved elements.
 21. The embolic implant of claim17, wherein the struts joining the elements are longitudinally displacedfrom each other.